John (or anyone contemplating building a new trailer themselves) here are a few tips.
Read the current rules - this Vehicle Standards Bulletin covers most of it:
http://www.infrastructure.gov.au/roa...sb1/index.aspx
You need stamped chains - the ones rated "25" for 2500kg should be fine. Mistake I learned the hard way.
The last trailer I made passed with ordinary chain.
Keep all your receipts so you can prove you built it from scratch.
Apply for your own VIN number here:
http://www.dpi.wa.gov.au/licensing/2494.asp
and get it stamped onto your Compliance Plate. Places like Martins Trailer Parts will supply & stamp one for $11.00
Keep everything as light as possible, but if you will be towing a full weight car your trailer will need brakes. I use mine for minis & mokes, total mass was 220kg but could be a lot lighter as I used free stuff.
This is the basic design drawing for mine, but a bit shorter:
http://users.bigpond.net.au/paulmart...nottrailer.pdf
